7mm-08 powder choice with 162 eld m

[estes640]

I am trying to decide between starting with one 4064 and varget for the 162 eldm bullets. I can load long and I'm shooting out of a 25" tube. Let me know if anyone else runs this or the 162 amazon bullet. Trying to get an idea on powder.

Ryan

 

[Laurie]

I've ended up using Viht N160 with the 160gn Sierra TMK which shouldn't be too different from the Hornady design. This is a long-FB set-up that sees COALS just under three-inches. Earlier attempts with faster burners such as the sometimes recommended IMR-4007SSC with the 160 TMK and 162 AMax produced a few promising groups but too low velocities before pressure signs first appeared.

It seems that slower burners in the 4831 class produce better results, at least IME. I tried Nitrochemie's RS62 which in the smaller 6.5s such as 260 and the Creedmoor works very well as an alternative to H4350, but it didn't shine in the 7-08/160, so the odds are that the 4350s won't either - but who knows? (The slightly slower burning IMR Enduron 4451 might suit though - something I'll try in due course.)

The case struggles with capacity and N160 loads are compressed. After starting with batched and prepped Winchester brass, I now use reformed Lapua 308 Win 'Palma' small primer cases and that limits case capacity still further.

RS62 (Alliant Re17 as it's called in the US) looked promising on a first go and also gives ~100 fps higher MVs than N160, but I want to avoid hot burning high-energy powders if possible. Viht N560 looks very promising on QuickLOAD too, but I've avoided it for the same reason. These high-energy propellants with infused nitroglycerin probably provide the best solution for this set-up if reduced barrel life is acceptable thanks to their increased density and high specific energies.

Finally, Viht N165 worked well with the old 175gn SMK in both groups and velocities, but was far too heavily compressed to the point of producing excessive and variable COALs. (As I also have a 284, there is no benefit in pushing the 7-08 to take this bullet weight anyway as the larger cartridge handles its powder charges with ease and gives higher MVs too.)

Starting over again, I'd almost certainly go for the AI chamber option as the little bit of extra case capacity should make it that bit easier to get the right performance mix.